There has
been much confusion over the term used in the anime, ‘Star
Warrior’ or ‘Hoshi no Senshi’ in Japanese. (Literally
‘Soldier of the star’) It hasn't always been clear to everyone exactly
WHAT a Star Warrior is, and there are many misconceptions.
However, through my translations of the original and a
little common sense, I’ve been able to figure it out.

The first
thing to remember is the English dub was wrong. They omitted
an entire group that was actually more prominent in the
original- the Ginga Senshi Dan, or Galaxy Soldier Army.
Whereas the dub calls nearly any soldier a Star Warrior,
this is far from the truth. (In addition, the dub removes
everything about the legends surrounding the Star Warriors.)

The Galaxy
Soldier Army (hereby to be called the GSA) is the name for
the army that fought against Nightmare. Anyone, in theory,
could be in this group. Meta Knight was a high ranking
member of it.

And Meta
Knight is also a Star Warrior. Star Warriors, it seems, were
commonly in the GSA- but not everyone in the GSA is a Star
Warrior!

Star
Warriors are not a species, and not anyone can BE a
Star Warrior.

While being in GSA is a conscious choice,
Star Warriors are far more special. They’re spoken of in
legends, said to be ‘the ones who will bring the universe to
eternal peace.’ (See episode 22 of the original.)

Kirby is a
Star Warrior (in addition to being ‘Kirby of the Stars’, but
I’ll get to that), though he’s not officially in the GSA.
Because Kirby is young- too young to have made a conscious
decision to be a Star Warrior- this suggests being one is a
matter of fate.

There
doesn’t seem to be any way to tell if a soldier is a Star
Warrior or not by looking at them, though it’s possible that
a Star Warrior can recognize another through some sixth
sense (as seen when Meta Knight first encountered Kirby in
episode one.)

So far the
only characters who are explicitly said to be Star Warriors
are Kirby, Meta Knight, and Knuckle Joe’s father. Yamikage
and Garlude were said to have been in the GSA, but it wasn’t
said they were Star Warriors, but they could have been. (Yamikage
was in the Ninja no Tokushubutai or Ninja Special
Forces section of the GSA.) Sgt. Dakonyo (Kit Cosmos) is not
a Star Warrior, only being a member of the GSA.

Sir Arthur
is said to be the leader of the GSA, but not that he’s a Star Warrior-
though being in such an important position it’s very likely
that he is.

Knuckle Joe
and Silica are not Star Warriors, suggesting it isn’t
hereditary. Joe is a Demon Hunter, which is apparently just
someone who hunts them on their own, and Silica doesn’t have
a title.

Episode
four, when MK tells Fumu about the war with Nightmare, he
says that the ‘Star Warrior Army’ was formed to battle
Nightmare. It isn’t until episode 22 in fact that the GSA is
mentioned. (When they first meet Dakonyo.)

I could be
that they came up with the idea of the GSA later, or it
could imply that the Star Warriors were just the first to
fight against Nightmare. As they are said to be legendary,
this is probably related to that… That they appeared for the
main purpose of fighting him.

From what
I’ve seen so far, the full legend of the Star Warriors is
never elaborated on though, so you’ll have to fill in those
blanks.

And as for
Kirby… Being a Star Warrior is special, but apparently he’s
the most special of all. He’s the only one given the ‘of the
Stars’ title, and in the flashback to the first episode at
least, it’s said he is a ‘savior’. (Can’t have an anime
without some obligatory religious refs!) Perhaps because he
was created by Nightmare, and yet he’s a Star Warrior is key
to it, but again they don’t seem to explain. (I’m hoping
they give us something in the last eps, but we’ll have to
see. I'll update if I find anything interesting.)

It should
also be mentioned that the concept of Star Warriors is
unique to the anime- they don't exist officially in the
games. Kirby is just a random guy with special powers there,
until HAL says otherwise. That doesn't keep you from writing
Alternate Universe things where there are Star Warriors in
the game timeline, but just remember it's not canon.